Bouncy Idle, Eventually Dies 94 Chevy Pickup

[Aaromars]

94 Chevy 5.7

It runs fine while driving, but when you stop, the idle bounces then eventually stalls
Replace IAC, TPS so far with no change

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Video shows whats happening

 

[Sean Buick 76]

I would replace all of the spark plugs, use a timing light to confirm that all 8 plug wires are getting spark. Of that checks out I would have a mechanic hood up a scanner and watch it while it’s running.

 

[tayto]

TBI pretty notorious for throttle body to intake gasket drying out and causing a vacuum leak.

 

[Aaromars]

Thanks, ill look into that

 

[Sabinoerc]

Check your fuel pressure. I had similar once and it was marginal fuel pressure

 

[Aaromars]

What would cause low fuel pressure beside pump? Pump was just replaced a couple months back


Would the Fuel Pressure Regulator have cause a problem?

 

[Sean Buick 76]

Yes I once chased an issue with fuel delivery and it ended up being the TBI fuel pressure regulator at the TB! I replaced the fuel pump and a ton of sensors before finding out the last thing it could be was this $20 regulator. I’m sure it’s $100 now

 

[Aaromars]

Im in the process of replacing that, also gonna check the wires and plugs next like you suggested, could i possible use a plug test light instead of a timing light?

 

[Sean Buick 76]

Yes a plug tester is better than a timing light but Dane purpose yes.

 

[Sabinoerc]

What would cause low fuel pressure beside pump? Pump was just replaced a couple months back


Would the Fuel Pressure Regulator have cause a problem?

A clogged fuel filter could cause low fuel pressure. I assume the fuel filter would have been replaced at same time as fuel pump and if so, at that point it’s easy to check fuel pressure as lines are open to put in the pressure fitting. Just good practice. I’ve read on these forums that some have had bad pumps out of the box.
I’m not saying this is your problem, just in my experience on these trucks fuel pressure is one of first things I’d check off whenever having some drivability problem. Just like checking your grounds are good and there are no vacuum leaks, etc,

Ive no experience with TBI pressure regulator and have read they can fail - but best way to check that is again, checking the fuel pressure. good luck!